Feed mechanisms for sewing machines



Sept. 29, 1959 M. R. PERLA ETA!- FEED MECHANISMS FOR SEWING MACHINES 2 Sheets-Sheet 1 Filed April 12, 1957 N 5 m. mm wm mm mm mm 4/ f r 7 n 8 -H mm :1? a Wm mu M NN H mm %s J7 A W A v 85 mm 9w MW ow a wm mw Q a 5 mm 8 mm s r .Mm 8 8 Y R H E 0 T a P. N NHK R Ee 0 V J T NP T Rp w A S a M W4 Y B WITNESS wafi w M. R. PERLA ETAL FEED MECHANISMS FOR SEWING MACHINES Sepfi. E29, 1959 2 Sheets-Sheet 2 Filed April 12, 1957 42 52 39 Fig. 4.

74 38 Fig. 5.

United States Patent FEED MECHANISMS FOR SEWING MACHINES Martin R. Perla, Bridgeport, and Stanley J. Ketterer,

Stratford, Conn., assignors to The Singer Manufactiurlng Company, Elizabeth, N.J., a corporation of New ersey Application April 12, 1957, Serial No. 652,454

10 Claims. (Cl. 112-215) This invention relates to work feeding mechanisms for sewing machines, and more particularly to a high quality work feeding mechanism for a cylinder bed sewing machine or the like in which space within the work supporting arm is restricted.

It is an object of this invention to provide a four motion work feeding mechanism for a cylinder bed machine having a straight, substantially flat feed advance motion.

It is another object of this invention to provide a work feedingmechanism for a sewing machine in which the feed actuating connections take the form of a sub-assembly which may be inserted as a unit into the sewing machine, thereby appreciably reducing the costof manufacture of a sewing machine embodying this feeding mechanism.

With the above and other objects and advantages in view as will hereinafter appear, this invention comprises the devices, combinations and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment in which:

Fig. 1 represents a top plan view of a work supporting bed of a sewing machine with the work supporting plate and the throat plate removed and with a portion of the machine frame broken away to expose the feed mechanism.

'Fig. 2 represents an enlarged vertical cross sectional view of the work supporting arm of the sewing machine of Fig. 5 is an enlarged cross sectionalview taken substantially along line 5--5 of Fig. '1, and

Fig. 6 is an enlarged top planview of the feed actuating mechanism sub-assembly, showing a portion of the feed driving shaft and of the stitch length regulating shaft.

Referring to Figs. 1, 2 and 3, the sewing machine to which the present invention is applied includes a hollow,

upwardly open, work supporting bed 11 of the so called .cylinder bed-or free ended variety which extends from an upright standard 12. Secured beneath the standard is a tubular machine supporting base 13. The standard 12 supports a bracket armwhich overhangs the bed 11 and carries the usual endwise reciprocatory needle and the main drive shaft of the sewing machine. Since the bracket arm and the parts carried therein may be conventional and have no direct bearing upon the present invention, these parts have not been illustrated in the drawings.

Journaled in a bearing boss 14 in the standard and a bearing boss 15 in the work supporting bed 11 is a rotary bed shaft 16 provided with a pulley 17 adapted to be The rotary hook is of the conventional variety employing a non-rotating bobbin thread case 22 engaged by a rotation restraining finger 23 carried by the bed.

'The upwardly open work supporting bed 11 is closed by a work supporting plate 24 and a throat plate 25 which extends over the rotary hook and is provided with a needle aperture 26 and slots 27 accommodating a feed dog 28.

As best illustrated in Figs. 1 and 2, the feed mechanism of this invention utilizes a feed bar 30 in the form of an elongated substantially horizontal plate disposed to extend lengthwise of the cylinder bed. At the outboard extremity the feed dog 28 is secured to the feed bar by the fastening screws 31. At the inboard extremity, the feed bar is bifurcated and has secured thereto by means of screws 32 a U-shaped bracket 33 of which the downwardly ofi'set limbs underlie the bifurcated portions of the feed bar to provide a pair of spaced jaws 34 disposed to embrace a bearing rod 35 fixed transversely of the machine bed 11. The spaced jaws 34 and the bearing rod 35 cooperate to define a pivotal axis extending crosswise of the bed and substantially parallel to the direction of feed, about which axis the feed bar pivots or tilts vertically. These parts also provide a guide means for sliding translatory movement of the feed bar substantially parallel to the direction of feed. The feed motion, therefore, is of the four motion variety and is a combination of these two movements, i.e. a sliding motion across the cylinder bed which provides the feed advance and return motions, and a tilting or pivotal motion about the axis of the bearing rod 35 which provides the feed lift and fall motions. The feed actuating mechanism by which these motions are derive will now be described. j

The feed actuating connections are for the most part carried as a sub-assembly in a base plate 36 secured by screws 37 to raised bosses 38 formed in the bottom of the work supporting bed 11. The base plate is formed with a pair of upstanding bearing lugs 39 and 40, the end surface of therbearing lug 39 being machined substantially vertically to provide a flat vertical bearing surface against which a bifurcated feed lift pitman 41 is pivoted by a fulcrum pin 42 secured in the bearing lug 39. The feed lift pitman embraces a feed lift cam 43 fast on the bed shaft 16 and, since the pitman is of the bifurcated variety,

it may be slipped into engagement with the cam when the base plate 36 is inserted into the bed. A substantially vertical feed lift link 44 is pivotally secured to the feed lift pitman by means of a shouldered pivot screw 45 which is threaded into the pitman. At the upper extremity, the feed lift link embraces the eccentric shoulder 47 of a pivot pin 48 which is secured in a split clamp portion of a block 49 by the clamp screw 50. These parts of the feed lift actuating connections form a portionof the feed actuating sub-assembly. After the base plate 36 of the sub assembly is secured in the bed 11, the block 49 is rigidly secured beneath the feed bar by means of a fastening screw 51.

Journaled freely in the upstanding bearing lugs 39 and 40, is a rod 52 having a collar 53 fast thereon at one side of the bearing 40. Fixed on the rod by means of a set screw 54 is a feed advance actuating member in the form of a rock frame 55 formed with a pair of spaced upstanding arms 56 and 57. A pivot rod 58 is freely journaled in a pair of aligned bores formed in said upstanding arms 56 and 57. Fast on the pivot rod 58 at one side of the arm 57 is a collar 59 and between the arms 56 and 57 is a feed advance driving link 60 made fast on the rod by set screws 61. Set into each of the upstanding arms 56 and 57 are vertically extending spherical headed pins 62 which provide the connections between the feed advance rock frame and the feed bar. As best illustrated in Figs. 1 and 2, the feed bar is formed with a circular aperture 63 which provides an aperture sized to snugly embrace one of the pins 62. The feed bar is also formed with an elongated slot 64 having a width accurately sized to the diameter of the other of the pins 62. The slot 64 may be provided economically by joining two spaced circular apertures as illustrated in the drawings, however, any form of slot will sufiice to prevent the binding of the parts provided only that the slot 64 is elongate in a direction toward the circular aperture 63. It will be appreciated that the aperture 64 is elongated to accommodate slight variations resulting from the allowable manufacturing tolerances of the parts.

The feed advance driving link is actuated by a feed advance eccentric cam 66 fast on the bed shaft 16. Since the pitman 65 is of the strap type, it cannot be pre-assembled as part of the sub-assembly on the base of the plate 36 unless the feed mechanism is to be assembled prior to the assembly of the bed shaft 16 into the machine. The pitman is pivotally secured to the driving link 60 by means of a pivot pin 67 which is secured in a split clamp 68 on the driving link by a clamp screw 69.

The pivot pin 67 is formed with a reduced eccentric end portion 70 which extends beyond the feed driving link and is embraced by an apertured slide block 71 which is confined in a slotted guide member 72 fast on a stitch length regulating shaft 73 journaled at one extremity in a bearing lug 74 extending upwardly from the base plate 36 and at the other extremity in the bearing boss 14 in the standard of the machine. A rock arm 75 clamped fast on the stitch regulating shaft is connected by means of a pivoted link 76 to a block 77 fast on a stitch length adjusting lever 78 fulcrumed in the standard. The lever is provided with a handle 79 projecting through a slot 80 formed in the front wall of the machine standard.

When the parts have been assembled as described above, the feed dog may be readily centered in the slots 27 of the throat plate by loosening the clamp screw 69 of the split clamp 68 formed on the feed advance link 60 so as to loosen the pivot pin 67. Since this extremity of the pin is eccentric and is embraced by the guide block 71, turning of the pin will effect a micrometer adjustment of the position of the feed dog with respect to the throat plate slots. The mechanism may then be locked in selected position of adjustment by tightening the clamp screw 69.

The height of the feed dog with respect to the throat plate may similarly be adjusted by means of the eccentric shouldered pivot pin 48 which joins the feed lift link 44 to the block 49 secured to the feed bar. Turning of the pivot pin 48 will effect a micrometer adjustment of the height of the feed dog which may be locked in selected position of adjustment by tightening the clamp screw 50.

In operation, the feed bar which is slidably pivoted with respect to the work supporting bed on the bearing rod 55, is given pivotal movement about the axis of the rod 35 by the feed lift actuating connections which causes the feed dog to rise and fall substantially vertically in the feed dog slots of the throat plate. Since the rise and fall of the feed dog is a comparatively small movement and the distance from the feed dog to the bearing rod 35 is comparatively large, the pivotal movement of the feed bar in rising and falling will shift the feed bar in an exceedingly flat are which will approximate, for all practical purposes, a straight vertical line movement.

The feed advance and return movements of the feed bar, which may become appreciable when larger stitch lengths are effected, comprise translatory movements of the feed bar, that is, a sliding movement of the feed bar on the bearing rod 35 parallel to the axis thereof. The feed motions thus occur in a straight line crosswise of the cylinder bed of the sewing machine so that even when the longest possible stitches are being made, the work fabrics will not be urged to one side or the other of the lineal direction of feed. Inclination or canting of the feed bar in the feed advance and return movement is prevented by means of the pair of arms 56 and 57 and the pair of spherical headed pins 62 carried thereby Which are em- 4 braced in the widely spaced apertures 63 and 64 in the feed bar.

The angular position of the slotted guideway 72 for the slide block 71 determines the magnitude of the movement of the feed advance pitrnan 65 which is transformed into a component effective to oscillate the rock frame 55.

The present invention thus provides a feed mechanism particularly adapted for use in sewing machines such as cylinder bed varieties in which space within the work supporting arm is at a premium. The feed motion moreover occurs in a straight line and not on an arcuate path, owing to the translatory movement of the feed-bar, so that lineal feeding of the work will obtain on all stitch lengths. Separate feed advance and feed lift actuating connections, furthermore, provide for a four motion feed movement in which the movement of the feed dog during the work feeding stroke is desirably fiat thereby providing a high quality feed mechanism.

Having thus described the nature of the invention, what We claim herein is:

1. A work-feeding mechanism for a sewing machine having a free ended work-supporting bed, comprising a. feed bar disposed within the confines of said bed, complemental bearing means on said feed bar and on said bed slidably and pivotally mounting said feed bar with respect to said bed for pivotal movement about an axis extending crosswise of said bed and for sliding translatory movement parallel to said pivotal axis, a feed dog carried by said feed bar, a feed-advance actuating member shiftably supported in said bed, means adapted to be actuated by said sewing machine for vibrating said feedadvance actuating member in a direction crosswise of said bed, a plurality of operative connections between said feed-advance actuating member and said feed bar, said connections disposed at spaced points on said feed bar between said feed dog and saidbearing means,.feedlift linkage carried within the confines of said bed and operatively connected to said feed bar, and means actuated by said sewing machine for vibrating said feed-lift linkage to impart said pivotal movement to said feed bar.

2. A work-feeding mechanism for a sewing machine having a free ended work-supporting bed, comprising, a feed bar disposed within the confines of said bed, a bearing rod carried crosswise in said bed, means formed on said feed bar and disposed in engagement with said bearing rod and providing for pivotal movement of said feed bar about said bearing rod and sliding movement of said feed bar along said bearing rod, a feed dog carried by said feed bar, an actuating mechanism sub-assembly for said feed bar, comprising, a base adapted to be secured within the confines of said work-supporting bed, a feedadvance rock frame journalled for oscillation in said base, spaced arms carried by said rock frame and disposed in operative engagement with said feed bar, a feedadvance pitman, operative connections between said feedadvance pitman and said feed-advance frame, a feed-lift pitman carried by said base, a feed-lift link pivotally secured to said pitman, and means pivotally securing said feed-lift link to said feed bar, and a shaft journaled in said work-supporting bed, and a feed-lift cam and a feed-advance cam fast on said shaft and disposed in operative engagement with said feed-lift and said feedadvance pitman respectively.

3. Mechanism in a sewing machine for feeding work fabric in a predetermined direction, comprising, a feed bar, complemental bearing means on said feed bar and on said sewing machine defining a pivotal axis substantially parallel to the direction of feed for pivotal movement of said feed bar and for translatory movement of said feed bar substantially parallel to the direction of feed, a rock frame journaled in said sewing machine on an axis substantially perpendicular to the pivotal axis of said complemental bearing means, said rock frame being formed with a spaced pair of arms disposed each in a. a. a

I myiu engagement with said feed bar, means op'eratively connected to said rock frame and adapted to be "driven by said sewing machine for rocking said rock frame to impart said translatory movement to said feed bar, linkage carried by said sewing machine and operatively connected to said feed bar effective to impart said pivotal movement to said feed bar, means adapted to be driven by said sewing machine for actuating said linkage, and a work-engaging feed dog carried by said feed bar.

4. Mechanism in a sewing machine for feeding work fabric in a predetermined direction, comprising, a bearing rod fixed in said sewing machine substantially parallel with the direction of feed, a feed bar slidably and pivotally mounted on said bearing rod for turning movement about the axis of said rod and sliding movement along said rod, a rock frame journalled in said sewing machine on an axis substantially perpendicular to the axis of said bearing rod and formed with spaced arms disposed each in engagement with said feed bar, means adapted to be driven by said sewing machine for rocking said rock frame to impart feed and return movements to said feed bar slidably along said bearing rod, linkage carried by said sewing machine and operatively connected to said feed bar effective to impart feed lift and fall movements to said feed bar pivotally about said bearing rod, means adapted to be driven by said sewing machine for actuating said linkage, and a work-engaging feed dog carried by said feed bar.

5. Mechanism in a sewing machine for feeding work fabric in a predetermined direction, comprising, a feed a bar a work-engaging feed dog carried by said feed bar and disposed substantially at the stitching point of said sewing machine, complemental bearing means carried on said sewing machine, and on said feed bar at a point remote from said stitching point, said bearing means defining a pivotal axis substantially parallel to the direction of feed providing for pivotal movement of said feed bar and for translatory movement of said feed bar substantially parallel to the direction of feed, a rock frame journalled in said sewing machine on an axis substantially perpendicular to the pivotal axis of said complemental bearing means, said rock frame being formed with a pair of arms disposed in engagement with said feed bar at spaced points between said feed dog and said complemental bearing means, means adapted to be driven by said sewing machine and operatively connected to said rock frame for rocking said rock frame to impart said translatory movement to said feed bar, linkage carried by said sewing machine and operatively connected to said feed bar at a point between said feed dog and said complemental bearing means and effective to impart said pivotal movement to said feed bar, and means adapted to be driven by said sewing machine for actuating said linkage.

6. Mechanism in a sewing machine for feeding work fabric in a predetermined direction, comprising, a feed bar, complemental bearing means on said feed bar and on said sewing machine ldefining a pivotal axis substantially parallel to the direction of feed providing for pivotal movement of said feed bar and translatory movement of said feed bar substantially parallel to the direction of feed, a rock frame journalled in said sewing machine on an axis disposed substantially perpendicular to the direction of feed, a pair of arms carried by said rock frame disposed each in engagement with said feed bar along a line substantially perpendicular to the direction of feed, means operatively connected to said rock frame and adapted to be driven by said sewing machine for rocking said rock frame to impart said translatory movement to said feed bar, linkage carried by said sewing machine and operatively connected to said feed bar effective to impart said pivotal movement to said feed bar, means adapted to be driven by said sewing machine for actuating said linkage, and a' work-engaging feed dog carried by said feed bar.

' '7. In a feed mechanism for a sewing "machine having a frame, a 'drive shaft journaled in said frame, a feedadvance cam and a feed-lift cam fast on said drive shaft, a feed bar slidably and pivotally mounted in said frame, an actuating mechanism sub-assembly for said feed bar, comprising, a base adapted to be secured-to said sewing machine frame, a feed advance rock frame journaled for oscillation in said base about an axis substantially perpendicular to that about which said feed bar is pivotally mounted in said frame, a driving link pivotally connected to said rock frame, a pitman pivotally connected to said driving link and adapted to embrace said feed advance cam, a feed-lift pitman pivotally secured to said base and adapted to embrace said feed-lift cam, a feed-liftlink pivotally secured to said feed-lift pitman, means pivotally securing said feed-lift link to said feed. bar, and means slidably and pivotally connecting said feed-advance rock frame to said feed bar.

8. In a feed mechanism for a sewing machine having a frame, a drive shaft journaled in said frame, a feedadvance cam and a feed-lift cam fast on said drive shaft, a stitch-length adjusting shaft journaled in said sewing machine frame and formed with a guide-slot disposed transversely of the axis of said shaft, a feed bar slidably and pivotally mounted in said frame, an actuating mechanism sub-assembly for said feed bar, comprising, a subassembly base, a feed-advance rock frame journaled for oscillation in said base, a driving link pivotally connected to said rock frame, a pitman adapted to embrace said feed-advance cam, means pivotally connecting said driving link to said pitman, and a slide block journaled on said means, a feed-lift pitman pivotally secured to said base and adapted to embrace said feed-lift cam, a feedlift link pivotally secured to said feed-lift pitman, means pivotally securing said feed-lift link to said feed bar, and means for securing said sub-assembly base to said sewing machine frame with said feed-advance rock frame disposed in slidable and pivotal engagement with said feed bar with the pivotal axis of said feed advance rock frame disposed substantially perpendicular to the axis about which said feed bar is pivotally mounted in said frame, and with said slide block slidably disposed in said stitchlength adjusting guide slot.

9. Mechanism in a sewing machine for feeding Work fabric in a predetermined direction, comprising, a feed bar, complemental bearing means on said feed bar and on said sewing machine defining a pivotal axis substantially parallel to the direction of feed providing for pivotal movement of said feed bar and for translatory move ment of said feed bar substantially parallel to the direction of feed, a rock frame journaled in said sewing machine on an axis substantially perpendicular to the axis of said complemental bearing means, a pair of spaced arms carried by said rock frame each of said arms being formed with a substantially spherically shaped free extremity, said feed bar being formed with a circular aperture disposed to accommodate a first of said pair of arms and formed with an aperture elongated in the direction toward said circular aperture and disposed to accommodate the second of said pair of arms, means operatively connected to said rock frame and adapted to be driven by said sewing machine for rocking said rock frame to impart said translatory movement to said feed bar, linkage carried by said sewing machine and operatively connected to said feed bar effective to impart said pivotal movement to said feed bar, means adapted to be driven by said sewing machine for actuating said linkage, and a work-engaging feed dog carried by said feed bar.

10. A work-feeding mechanism for a sewing machine having a machine frame provided with a bed and an actuating shaft journaled in said bed, comprising, a feedbar disposed within said bed and extending longitudinally therof, a feed-dog secured to one end of said feed-dog, a bearing rod fixed in said bed with the longitudinal axis of said bearing rod arranged transversely of said bed 7 and parallel to the normal direction of feed of said workfeeding mechanism, bearing means secured to that end of the feeds-bar remote from the feed-dog and engageable with said bearing rod providing for pivotal movement of said feed bar about the axis of said bearing rod and for sliding translatory movement of said feed bar along said bearing rod, feed lift connections disposed within said bed for actuation by said actuating shaft and operatively connected to said feed-bar at a point adjacent said feed dog to impart pivotal movement to said feed bar about said bearing rod, and feed advance and return connections disposed within said bed for actuation by said actuating shaft to impart sliding translatory movement to said feed bar along said bearing rod, said feed advance and returnconnections including a rock frame pivoted on said ,bed on an axis substantially perpendicular to the longitudinal axis of said bearing rod, and having a first arm operatively connected to said-feed bar near the feeddog end thereof and a second arm operatively connected to said feed bar at a point remote from the first arm and near the other end of said feed bar.

References Cited in the file of this patent UNITED STATES PATENTS 2,442,647 Fischbein June 1, 1948 2,725,023 Ayres Nov. 29, 1955 2,808,793 Ayres Oct. 8, 1957 

